Earthquake Early Warning: Travel-Time Diagram & Seismograms

Earthquake early-warning systems don't predict quakes — they win a race against physics, and seismologists have always read that race off a travel-time diagram rather than a spatial map. This simulation draws the real distance–time plot for the fast, weak P-wave and the slow, damaging S-wave as two straight lines through the origin, marks a monitoring station near the epicenter and a city at a chosen distance, and then synthesizes live seismogram traces at both locations from Ricker wavelets whose amplitude falls off as 1/r — exactly the geometric spreading real body waves undergo — so you can watch the signal actually build, peak, and decay as each wavefront passes, not just see a timer count down.